In the existing institutions, such as medical institutions and sanatoriums, rehabilitation for recovery of a physically impaired person is performed by an exercise therapy to retrieve a physical ability of a moving part (such as a hand, an arm, a shoulder, a waist, a knee, an ankle, etc.) of the person (human body).
The medical rehabilitation of this type is performed by adding load to or applying external force to the muscles around the moving part to bend or stretch a joint of the moving part, in order to recover the physical ability of the moving part which decrease to direct or indirect factors, such as an injury or illness.
There are various methods of applying a load or an external force, such as a simple method using a weight or an elastic band and a machine-implemented method using a dedicated load machine or instrument. In any case, rehabilitation is carried out according to instructions of a doctor or a physiotherapist.
Patent Document 1 discloses a rehabilitation device which performs rehabilitation (or ergotherapy) by an exercise cure. The rehabilitation device includes an arm extending from the base part and a holding part disposed at a leading end of the arm. Using the rehabilitation device, the person who is subjected to rehabilitation can perform selectively one of several exercises in accordance with the recovering situation of the joint or muscular force of the person, the exercises including a compulsory exercise in which the limb of the person is compulsorily moved by an external force, an automatic exercise in which the limb of the person is actively moved, such as an isotonic motion, a uniform motion, and a resistance exercise.
The arm is the multi-axial link including two or more drive shafts. The arm moves the holding part to an arbitrary position in a movable range and changes the posture of the holding part. The arm moves along with the rail. The holding part is attached to the limb of the person who is subjected to rehabilitation. An angle sensor and a speed sensor are disposed on each of the drive shafts.
As disclosed in Patent Document 1, the rehabilitation device is arranged to acquire load information including the information of myoelectric signals produced by main muscles of the limb, the information of the position and posture of the arm, the detection value of a torque sensor attached to the drive shaft, etc., in order to measure the load which is actively produced by the limb of the person subjected to rehabilitation.
The acquired load information is used to perform an automatic assist. When the person moves the limb with his intention at the time of the automatic assist, a force larger than the force of the person is exerted on the limb by the auxiliary operation of the arm performed by the rehabilitation device based on the load information acquired at this time.
Patent Document 2 discloses a portable electromyogram and physical movement measuring device which is adapted for quantitatively analyzing the degree of recovery of the person by rehabilitation. This measuring device includes a myoelectric sensor and a physical movement sensor. The myoelectric sensor detects a myoelectric potential signal as a biosignal. In Patent Document 2, an acceleration sensor is used as the physical movement sensor. These sensors are disposed at symmetrical positions on each of the right-hand side and the left-hand side of the limbs of the person respectively, and the sensors disposed on one side cover the measuring part of the person while the sensors disposed on the other side cover the healthy part of the person.
The measuring device of Patent Document 2 transmits the detection signals output from the respective sensors, to an external personal computer through a radio transmission unit of the measuring device. The measurement data of the moving condition of the person acquired from the sensors is converted into numerical data, and displayed on the computer display. Viewing the numerical data on the display, a doctor or a physiotherapist analyzes quantitatively the effect of the rehabilitation to the person.
Patent Document 3 discloses a motor-driven auxiliary device which is attached to a knee joint of a person and assists the person who walks up a staircase. The motor-driven auxiliary device includes an actuator, an angle sensor, a pressure sensor, and a myoelectric sensor that detects a myoelectric potential as a biosignal. The angle sensor detects a rotational angle of the knee joint. The myoelectric sensor detects the degree of strain of the muscles. The pressure sensor detects a load or a weight on the leg. The motor-driven auxiliary device determines whether the motion of the person is a staircase walking operation based on the detection signals from these sensors and controls the driving of the actuator by using the detection signals of these sensors as a trigger.    Patent Document 1: Japanese Laid-Open Patent Publication No. 10-258100    Patent Document 2: Japanese Laid-Open Patent Publication No. 2005-278706    Patent Document 3: Japanese Laid-Open Patent Publication No. 7-163607